Feed chuck



F. E. GREEN FEED CHUCK Nov. 25, 1930.

Filed Feb. 18, 1930 Patented Nov. 25,1930

bmT'E STATES pA'renrorrlcsf a FRANK GREEN, orrrrrrsnunen, r NnsYLvAnIA i FEED annex,

Application filed. February 1s, 1930. Seri a1 Nolg 1 2L9345.

In certain classes of machinery, such" for instance assingle or" multiple spindleautomatic screw machines, aieed chuck 1s employed for intermittently feeding forwardly 5thestock, and my invention relates to such feed chucks. 1

A common form of such chuck isa tubular pieceor spring or tool steel llfLVlIlgltS wall slit longitudinally and inbent towar d the axis of the tube to'form gripping portions or fingers. Such feed chucks are inefiicient in operation andshort lived, asthe fingers become worn and present sharp edges to the stock, thusmarring the latter, and the gripping action of'the spring meta-lis impaired and thus the stock is not fed uniformly.

*Wherieither of these contingencies occur the entire chuck, made of expensive material, must be scrapped, 0r first annealed, then machinedand then rehardened, often with poor results. 0' 1 Again'in the case offeed chucks ofthe character above described there are no-means for adjusting or regulating the action ofthe "grippingfingersasfor instance to compensate for wear or loss 'of tensions I r Inrnyj improved feed chuck the grippers are separate elements which are removably and interchangeably mounted in a tubular worn or lose their tensionthey can be quickly and conveniently removed from-the holder and others substituted in theirplace. Thus the loss of theentire chuckis avoided.- v

'Againmy improved feed chuck is provided with means for regulating and adjusting the gripping action of the fingers so as to obtain the most. efficient and uniform feed for a given character or cross-section of stock orto compensate for finger wear or loss of tension. 7

l 2 Where different diameters or cross section 1 St e 0 be'worked, suitable grippers are installed in the holder. 3 7

Other novel features of constructiomand the following description.

In the accompanying drawings, wherein j p i I have illustrated a practical embodiment of 5 0 the principles of my invention, Fig. 1 an the grippersshown inFigs; 5and 6.

holder, so-that shouldflthe grippers become of arrangement of; parts, will appear from elevationof thefeed chuck with a length of ing two grippers instead of three pers shownin Figs. 2,3 and 4. i U

"Fig. 11 is a broken perspectiveof oneor" 1 Referring fii'stto Figs. 1,2 and?) of the drawings, 1 represehtsthe tubular holder 1 of' the-chuckfi The holder isa steel tube, such as ai-piece of seamless tubing. The rear end of theholdefiis-interiorlythreaded as at2- so that thelnipple 3 may be screwed into the same. The'othe'r end of the nipple is screwed 'into the feed tube 4 of the screw machine. .Thejnipple 3' is provided with a. central annularshoulder 5 which may serve to limit the: insertionpfl the nipplei'nto an associated element or tor the application of a wrench or other tool for turning th enipplel The front end ofthe nipple 3Which is inserted into the holder-1 has its annular edges "bevelled to form an annular wedging shoulde'r'6. -The front end of the tubular holder 1 is providedwith an annular internal Wedging shoulder? which may, if desired, be

formed by-inwardly upsetting the end of the holder. The shoulders 6 and Tare opposed Fig.1 2is an enlarged longitudinal section Fig. 10is a perspectiveof one of the gripii to each other and maybe caused toapproach it or diverge by. screwing in or unscrewing the nipplerelative to theholder. l

The grippers are formed of: strips of spring steel material .first cut and: pressed into shape and then tempered. The endportionsf8of the strips arelof arcuate cross sectional shape and together fitthe boreof the holder :adjacent to ends while the intermediate portions are narrowed and pressed inwardly to form the spring fingers 9 which bear against and grasp the stock. Where the stock is round, the fingers are arcuate to fit the stock.

In Figs. 2, 3 and 4, three grippers are shown employed to grasp the round stock 10 while in Fig. 9 but two grippers are employed.

One of the grippers employed in Figs. 2, 3 and 4 is illustrated in Fig. 10.

Where stock of square crosssectional shape is to be gripped by the chuck, as shown at 10 in Figs. 5 and 6, I prefer to use the form of grippers illustrated at 8 in Fig. 11, four of the same being employed, the end portions of the grippers being arcuate to fit together in the bore of the holder while the intermediate or finger portions of the grippers are fiat to bear against the four sides of the square stock 10.

lVhere hexagonal stock, such as shown at 10 in Figs. 7 and 8, is to be gripped by the chuck .I prefer to employ three grippers 8 9 with their fiat fingers gripping alternate sides of the stock.

The ends of the grippers are beveled as at 11 to mate with the wedging shoulders 6 and 7 so that by screwing in the nipple 3 relative to the holder 1, the rippers will be compressed longitudinally and thus the fingers will be forced inwardly toward the axis of the holder. Thus by adjusting the nipple relative to the holder the grip of the fingers on a predetermined diameter or shape of stock may be regulated so that the feed will be proper and uniform.

In like manner any wear or loss of resiliency or gripping power in the fingers may be taken up or compensated for. r

The stock is easily inserted through the chuck without danger of breakage of machine parts.

IVhen it is desired to remove or replace the grippers, the nipple is unscrewed from the end of the holder, the grippers pulled out and new ones substituted, and the nipple screwed into place.

It is obvious that when the chuck is to be changed to suit different stock or becomes inefficient from use or other causes, the only replacement is that of the grippers, instead of the whole chuck as is now necessary.

My improved chuck is of inexpensive con struction but strong and durable.

One striking'advantage of my invention arisesrfrom the fact that. finished or polished stockrmay be'fed with'it without-danger of the stock becomingscratched or marred.

Again the end of the stock-slips easily into the chuck and thereforeit isnot necessaryrto grind or bevel .theend of the-stock preparatory to'placing it. in the'machine. Likewise ter is retreated, when the chuck is advanced the end of the stub will easily reenter the stub without danger of breakage.

lVhat I desire to claim is 1. In a feed chuck, the combination of a tubular holder, a plurality of spring metal grippers having end portions to fit the holder and removably mounted in said holder, said grippers having intermediate portions bowed inwardly toward the axis of the holder to form stoclcgripping fingers, and means for compressing the grippers longitudinally to increasetheir stoclcgripping action.

2. In a feed chuck, the combination of a tubular holder, a plurality of spring metal grippers mounted within the holder and having end portions to fit the holder, said grippers having portions bowed inwardly toward the axis of the holder to form stock-gripping fingers and a wedging abutment positioned adjacent to each end of the holder and engaging the ends of the grippers.

3. In a feed chuck, the combination of a tubular holder, a plurality of spring metal grippers mounted within the holder and having end portions to fit the holder, said grippers having portions pressed inwardly toward the axis of the holder to form stockgripping fingers, a wedging abutment positioned adjacent to each end of the holder and engaging the ends of the grippers, and means for varying the distance between the abutments whereby to regulate the action of the fingers.

4. In a feed chuck, the combination of a tubular holder, an internal wedging shoulder at the one end of the holder, a member inserted into the other end of the holder and forming a second internal shoulder, a plurality of spring steel grippers having end portions to fit the holder mounted in said holder between said shoulders, the intermediate portions of the grippers being bowed inwardly to form stock-gripping fingers.

5. In a feed chuck, the combination of a tubular holder having an internal wedging shoulder at one end, a member screwed into the other end of the holder and forming a second internal wedging shoulder, and a plurality of spring metal grippers having end portions to fit the holder held in said holder between said shoulders, the intermediate portions of said grippers being bowed inwardly to form stock-gripping fingers, and the compression of said fingers being regulated by the degree of insertion of said member in said holder.

Signed at Pittsburgh, Pa., this 25th day of January, 1930.

FRANK E. GREEN.

when but ashort stub of the stock is left and 'athe-same ispulled outiof the chuckaszthe lat- 

